Abstract: A modular element has an internally hollow body (2) made of plasstic material and exhibiting a parallelepiped horizontally-disposed configuration with a transverse section symmetrically diverging from a top portion (4) to a base portion (5). The opposite end surfaces (9, 11) of the body (2) are respectively provided with a coupling lug (8) and an engagement seat (10) matching the shape of said coupling lug. The coupling lug (8) of each modular element (1) is adaped to be fitted in the engagement seat (10) of a contiguous modular element (1b) for the purpose of consecutively connecting several modular elements together. In an alternative embodiment a modular element (12) is provided, at its opposite sides, with two coupling lugs (8) each adapted to be fitted in an engagement seat (10) exhibited by a contiguous modular element (13).